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Date: Fri, 27 Jul 2001 21:45:07 +0400
From: Hans Reiser <reiser@namesys.com>
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To: Andrew Morton <akpm@zip.com.au>
CC: Joshua Schmidlkofer <menion@srci.iwpsd.org>,
        kernel <linux-kernel@vger.kernel.org>, Chris Mason <mason@suse.com>,
        "Gryaznova E." <grev@namesys.botik.ru>,
        "Vladimir V. Saveliev" <monstr@namesys.com>
Subject: Re: ReiserFS / 2.4.6 / Data Corruption
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Andrew Morton wrote:
> 
> Hans Reiser wrote:
> >
> > Andrew, can you do this such that there is no disruption of our
> > disk format, and make a mount option
> > out of it, and probably we should use this patch....
> 
> I'll defer to Chris :)

Yes, I'll let him think carefully through the details of how it affects ordering of the writes.


> 
> There's no disruption to disk format - it just simulates
> the user typing `sync' at the right time.  I think the
> concept is sound, and I'm sure Chris can find a more efficient
> way...

Oops, sorry, you changed the in-ram not the on-disk sb....

> 
> > After you make a mount option out of it, grev will benchmark
> > it for us using the usual suite of benchmarks.
> >
> 
> Ordered-data is a funny thing.  Under heavy loads it tends
> to make a significant throughput difference - on ext3 it
> almost halves throughput wrt writeback mode.
> 
> But this by no means indicates that writes are half as slow;
> what happens is that metadata-intensive workloads fill the
> journal up quickly, so the `sync' happens more frequently.
> Under normal workloads, or less metadata-intense workloads
> the difference is very small.
> 
> During testing of that little patch I noted that the
> disk went crunch every thirty seconds or so, which is good.
> Presumably the reiserfs journal is larger, or more space-efficient.
> 
> -

Thanks Andrew